This invention relates to a radio paging receiver and, in particular, to a radio paging receiving having a message display function.
One of conventional radio paging receivers of the type described is disclosed in Japanese Utility Model Prepublication No. 92243/1990 (Title of Invention: Paging Receiver with Message Receiving Function). The radio paging receiver disclosed therein has a function of protecting unconfirmed messages memorized in a first or main memory area of a message memory of, for example, an RAM (random access memory) until a possessor of the radio paging receiver confirms the unconfirmed message under consideration. The unconfirmed message is a message which is not yet confirmed by the possessor. For this purpose, the radio paging receiver comprises in the message memory, in addition to the first memory area for successively memorizing a plurality of received messages, a second or subsidiary memory area for memorizing an oldest reception unconfirmed message among the unconfirmed messages that is erased from the first memory area. When the oldest reception unconfirmed message is transferred from the first memory area to the second memory area and is thereby memorized in the second memory area, this is announced for a predetermined time interval.
In the above-mentioned conventional radio paging receiver, the reception message must be transferred from the first memory area to the second memory area when the first memory area has no vacant or empty area (that is, the first memory area is put in a full state in which the first memory area is filled with the reception messages), in order to prevent erasure of any unconfirmed message before it is confirmed. Necessity of the second memory area and a transfer function of the reception message from the first memory area to the second memory area results in a complicated structure and an increased cost of the radio paging receiver.
In the above-mentioned radio paging receiver, a confirmed message may possibly be erased even if it is protected as a protected message (with a protected attribute).